<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
        <style>
            div{
                text-decoration: underline;
            }
            /* none是无 underline是下划线 line-through是删除线 oveline是上划线 */

        </style>


</head>
<body>
    <div>这是div标签</div>
</body>
</html>